<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        class Student{
            constructor(){
                console.log("学生")
                this.name="James"
            }
        }
        let s=new Student()
        class Student1{
            constructor(name,age){
                console.log("学生")
                this.name=name
                this.age=age
            }
            sayHello(){
                console.log("Hello")
            }
        }
        let s2=new Student1("zhangsan",18)
        console.log(s2)
        s2.sayHello()
        let product={
            name:"James",
            height:183,
            gender:"male"
        }
        console.log(Object.keys(product))
        console.log(Object.values(product))
        console.log(Object.entries(product))
        let entries=Object.entries(product)
        for(item of entries){
            console.log(item)
        }
        for(index in entries){
            console.log(entries[index])
        }
    </script>
</body>
</html>